This invention concerns air induction systems for internal combustion engines. Modern engines for automotive power plants incorporate one or more resonator chamber devices in the air induction system in order to reduce engine noise. Conventionally, each resonator device comprises a separate component which must be connected into the induction system typically using hoses and clamps to connect the device to the air cleaner and throttle body. This involves significant labor, extra parts, and potential leak points allowing entry of dust.
In an effort to simplify the air induction system and lower costs, the air cleaner sometimes includes a resonator chamber in the housing into which the air cleaner element is installed. An example of such a system is shown in U.S. Pat. No. 4,790,864, issued on Dec. 13, 1988 for a "Compact Engine Air Cleaner with Integrated Components".
Resonator devices include both expansion chamber and Helmholtz resonators which are each designed to attenuate noise in different frequency ranges. Even where one type of resonator is integrated into the air cleaner housing, typically the other type is often installed as a separate component, although integration of both types in a separate component is shown in U.S. Pat. No. 5,424,494, issued on Jun. 13, 1995 to the assignee of the present application.
Copending application U.S. Ser. No. 08/842,252 filed on Apr. 24, 1997, assigned to the same assignee as the present application, attorney docket No. 97P7659US, describes a connector hose between the air cleaner and throttle body which has both types of resonator integrated with the connector hose.
Automotive air cleaner elements often are rectangular in shape and are sealed by engagement of a large rectangular cover around the entire perimeter of the seal. The air cleaner housing is usually of molded plastic, and larger molded structures sometimes are slightly warped, creating leak points where dust can bypass the air filter and enter the engine.
More costly stronger plastic materials are often used to avoid this problem, thus increasing costs.
An object of the present invention is to provide an air induction system having an air cleaner which incorporates both an expansion chamber and a Helmholtz resonator.
Another object of the present invention is to provide an air cleaner assembly for an automotive air induction system which does not rely on establishing complete sealing engagement of covers or other housing parts with the filter element.